Salesforce Report Considerations for Changes to Picklist Values and Record Types

Picklists
When a picklist value has been renamed, the filter criteria in the reports and views are not automatically updated.  Users must manually update any report filters that reference the previous picklist value.  

If you instead replace the picklist value, you should not need to modify existing report filters.  Since replacing the picklist value does not delete the existing value, both the new and existing values will appear when users edit report filters.

See Also: Difference between renaming and replacing a picklist value


Record Types
In the ‌case of a record type, the label can be changed through the standard User Interface. This will not impact any reports as the filter criteria are automatically updated with the new record type label once run. 

The Record type has a Label and another internal use field called Record Type Name. Changing the label only changes how the field is labeled as in reports etc.The internal name is used by Salesforce to recognize and identify the specific record type. 

If you change the label, and do not change the name, reports will not be affected.